This invention concerns a process for generating smooth surfaces on objects made of polymers of ethylene, propylene, butadiene, and polystyrene.
The surface which results from the process of the present invention plays an important role in almost all sectors of plastics processing. Sliding and frictional resistance, permeation characteristics, wettability, and gloss, to name only a few of the properties of the polymer surfaces, are critically influenced by the morphology of the surface. A surface that is as smooth as possible, even on a microscopic scale, minimizes all interactions between the surface and media which are in contact with it. For example, the rates of permeation and swelling processes are greatly influenced by the available active surface of the polymer (see "Formation of barrier layers in hollow plastic objects", [Sperrschichtbildung bei Kunststoffhohlkorpern], published by Verein Dt. Ingenieure, VDI Verlag, ISBN 3-18-234-121-9, pp. 20-21). In addition to these advantageous properties of a smooth surface as compared with the matte surfaces such as those exhibited at present by objects made of, for example, HDPE, a smooth glossy surface also has a decorative effect in many sectors. High-gloss surfaces are usually a prerequisite for good marketability of semi-finished products (such as films) and finished parts (such as household articles).
The present invention provides a process for generating smooth surfaces on objects made of polymers of ethylene, propylene, butadiene, and polystyrene, which as a result of the minimization of the active surface produced thereby, exhibit extremely low interactions with media that are in contact with them.